Hygrometer



I?" mmum H. HASTINGS HYGROMETER Filed Feb. 23, 1953 O H UNI DIIY INVENTQ R Hg/FBERTMST/NGS Patented Oct. 29, 1935 I ztnzzz UNITED STATES PATENT OFFIQE HYGROMETER Herbert Hastings, Brighton, N. Y.

Application February 23, 1933, Serial No. 657,998

6 Claims. (01. 12-24) This invention relates to hygrometers and has for its object to provide a construction for such an instrument in which the increase and decrease of the length of its hygroscopic element is accurately transmitted to an indicator to indicate the amount of moisture in the atmosphere.

Another object of this invention is to so construct the hygrometer that its hygroscopic element can be quickly and easily adjusted.

A further object of this invention is to provide a novel mounting for the hygroscopic element of the hygrometer.

These and other objects of this invention will become more readily apparent from the detailed description of it which follows, reference being had to the accompanying drawing in which Figure l is a front elevation of the hygrometer.

Figure 2 is an enlarged detail perspective view of the rear of the dial of the hygrometer and the operating unit mounted thereon.

Figure 3 is a vertical sectional view of the hygrometer and lengthens as it increases.

In so doing an indicating hand is moved over a scale which is calibrated with relation to the movement of the hand to indicate the relative moisture contents of the atmosphere.

. As illustrated in the figures, the hygrometer comprises a case made up of the shell I which is enlarged near the open end to provide the annular dial seal 2 therein. A flange 3 surrounds the open end of the shell and forms a seat for the edge of the crystal 4 to be clamped thereto by means of the bezel 5. The bezel encircles the flange 3 and its rear engages behind it. The front of the bezel extends from the rim of the crystal first forwardly and then rearwardly to provide a spring flange 6 which overhangs the edge of the crystal and yieldingly clamps the rim thereof onto the flange 3 of the shell of the case.

The operating unit of the hygrometer is mounted on the back of the dial I and comprises a vertical base 8 having the bearing bracket 9 bent rearwardly and upwardly therefrom near the bottom thereof.

he steft s oc ted between the bearing bracket 9 and the dial I and the reduced outer ends of this staff project thru and are mounted to rock in suitable bearings provided in the dial 1 and the bracket 9 and carry in front of the dial 1 the indicating hand 5 II and in back of the bracket 9 the crank I2.

At the top of the vertical base 8, a horizontal bracket I3 is bent out therefrom and this bracket has a lateral extension I4 which projects to one side of the base and has the clamping plate I5 10 bent up therefrom parallel thereto to provide a narrow groove I5 between them. A further extension ll of the bracket l3 extends from the outer end of the narrow groove I6 substantially at right angles thereto and slightly curves to- Ward the base 8.

The hygroscopic element I8 used for the operation of this instrument comprises a flat ribbon, one end of which projects into the narrow groove I5 and is fixedly clamped in place therein by the clamping plate I5. From the outer end of the groove the hygroscopic element ribbon extends in front of the curvcd'extension 11 to the staff iii which it partially encircles to have its end project into the longitudinal groove 20 thereof. A clamping pin 2| is placed in the groove 20 on top of the end of the element ribbon and one side of the groove 20 is peened over at I9 and partially overhangs the pin to hold it and the end of the element firmly anchored in place therein.

A spring. finger Z2 is provided for the purpose of taking up the contraction and expansion of the hygroscopic element and keeping it uniformly tensioned at all times. This spring finger has its upper end fixedly supported in'the bracket 23 which is bent up from the side of the base 8 below the bracket I3. The lower end of the spring finger projects into the hole IZA provided in the top of the crank I2. The tension of the spring finger is such that it tends to turn the crank I2 40 toward the leftin Figure'2 and in so doing rotates the staff I2 in a counter clockwise direction in Figure 2 whenever the hygroscopic element ribbon is lengthened on the increase of the humidity in the atmosphere. This movement of the staff in turn swings the indicating hand I I to the right in Figure 1 to indicate the moisture increase'on the calibrated scale of the dial.

The shortening of the hygroscopic element ribbon causes the end, which is attached to the staff, to unwind therefrom against pressure of the spring finger 22. This takes place whenever the humidity in the atmosphere decreases. In unwinding, the hygroscopic element ribbon causes the staff to rotate in a clockwise direction in Figure 2 and swings the indicating hand I l to the left in Figure 1 to indicate the moisture decrease in the atmosphere on the calibrated scale of the dial.

Should it be found necessary in the calibrating of the hygrometer to shorten the active length of the hygroscopic ribbon element IS, a spring clip 24 is used to clamp the upper portion of the element ribbon to the extension I! of the bracket l3. This spring clip is provided with a pair of parallel spring fingers 25, one of which engages one side of the hygroscopic element ribbon while the other engages the opposite side of the extension l1. extension together wherever the fingers make contact therewith. In this way any portion of the hygroscopic element ribbon which is located along the extension I! above the clip may be held inactive by the spring clip-'24 so that its contraction and expansion cannot affect the movement of the staff l0 and its indicating hand II. In order that a proper adjustment of the hygroscopic element ribbon can be effected on the extension I'I, the extension is normally curved away from the ribbon element and does not make contact therewith except where it is held against it by the fingers of the spring clip 24.

To provide circulation of air thru the case of the hygrometer in order to have the hygroscopic element surrounded by theatmosphere to be measured for its humidity, the shell I of the case is perforated by suitable ho1es'26 in the side thereof.

The original adjustment of the hygroscopic element for the purpose of setting the instrument is made by means of the lateral extension [4 of the lug .l3. This extension is bendable in the plane in which the hygroscopic element expands and contracts .and by bending it either toward or away from the staff the distance between the fixed anchoring point of the hygroscopic element and the staff is eithershortened or lengthened and the'position of the indicating hand correspondingly moved to the right or left for its predetermined starting position.

I claim:

1. In a hygrometer, the combination of a dial, a rock shaft mounted on said dial, a pointer at one end of said rock shaft and a crank at the other end of said rock shaft, 3, hygroscopic element wrapped around'and fastened to said rock shaft with one end thereof and adjustably anchored to said dial with the other end thereof and a spring arm fixedly anchored on said dial with one end thereof and slidably engaging said crank with the other end thereof to cause said rock shaft to turn on the expansion of said hygroscopic'element.

2. In a hygrometer, the combination of a dial, a rock shaft mounted on said dial, a pointer at one end of said rock shaft and a crank at the other end thereof, a hygroscopic element wrapped around and fastened to said rock shaftbetween said crank and said pointer with one end thereof This clamps the element ribbon and-"the and fixedly attached to said dial with the other end thereof, a spring arm having one end fixedly anchored on said dial and having the free end slidably engaging said crank to cause said rock shaft to turn on the expansion of said hygroscopic element.

3. In a hygrometer, the combination of a base, a bendable anchoring lug on said base adapted to be bent into a predetermined position so as to maintain itself in said position, a staff mounted to rock on said base, a hygroscopic element fixedly anchored at one end in said bendable lug and fixedly anchored to the periphery of said staff at the other end thereof, and a spring member carried by I said base and adapted to rotate said staff in one direction against the resistance of said hygroscopic element.

4. In a hygrometer, the combination of a base having a hygroscopic element mounted thereon, a self-contained anchoring bracket adapted to be bent into a predetermined position and adapted to maintain itself in said position; fastening means carried by said bracket, astaff mounted to rock on said base, said hygroscopic element having one end thereof held fastened to said anchoring? bracket by said fastening means and the other end of said hygroscopic'element attached to the periphery of said staff, a spring anchored on said base and connected to said staff to normally turn said staff in one direction against the resistance of said hygroscopic element.

5. In a hygroineter, the combination of a base having a hygroscopic element mounted thereon, an anchoring bracket bendable in the direction of expansion and contraction of saidhygroscopic element on said base, fastening means carriedby said bracket, astaff mounted to rock on said base, said hygroscopic element having one end thereof held fastened to said anchoring bracket by said fastening means and the other end of said hygroscopic element attached to the periphery of said Staff, a spring anchored on said base and connected to said staff to normally turn said staff in one direction against the resistance of said hygro- "scopic element and means cooperating with said bracket to hold a portion of said'hygroscopic element inactive.

6. In a hygrometer; the combination of a base, an anchoring bracket on said base,-a staff mounted to rock on said base, a hygroscopic element fixedly anchored at one end in said anchoring bracket and fixedly anchored torthe periphery of said staff at the other end, aspring member carried by said base and connected to said staff to rotate said staff in one direction against the resistance of said hygroscopic element, an extension on said anchoring bracket extending along side of said hygroscopic element and a spring clip clamping said hygroscopic element against said extension to hold a' portion thereof inactive.

HERBERT HASTINGS. 

